About the Keyboard Tester
What is a keyboard tester?
A keyboard tester is a tool that shows which keys on your keyboard send a signal when pressed. Each press normally fires a keydown event in the page. Its code value, defined in the W3C list of keyboard code values, names the physical key rather than the character it types.
People also call it a keyboard checker, a key tester or a keyboard diagnostic tool. Because our tester reads those position codes, Left Shift and Right Shift count as separate keys, and so do Enter and Numpad Enter. The correct key lights up on AZERTY and QWERTZ layouts too.
What do the key colors mean?
Each key on the map changes color to show what the tester received.
- A plain key means not pressed yet. The tester hasn't received anything from it since the page loaded or since you pressed Reset.
- Green with a check mark means it works. The tester received a press or a release from that key.
- Blue means held down. The key is pressed right now, and a key that stays blue after you let go is probably stuck.
- Amber with an exclamation mark means chatter. The key registered a new press within the chatter limit after it was released.
- A dashed outline means the key can't be tested. That's Fn on the 60% layout.
How do you test your keyboard keys?
Pick the layout that matches your keyboard, then press every key once.
- Match the layout. Choose Full size, Tenkeyless or 60%, then ISO if your Enter key is two rows tall or ANSI if it's one. Pick Mac labels for an Apple keyboard.
- Start the test. Click or tap the keyboard map so the status reads Testing.
- Press every key once. Work row by row, including the left and right Shift, Ctrl and Alt keys.
- Check what is left. Open the Keys not pressed yet list to see every key that is still plain.
- Save the result. The Copy results button copies a plain-text summary for a repair shop or a return request.
How many keys does each keyboard layout have?
The standard full-size ANSI layout has 104 keys, and the ISO version has 105.
ISO keyboards, common in the UK and much of Europe, add a key between Left Shift and Z and use a taller Enter key. Smaller layouts drop whole groups of keys. On the 60% layout, the tester counts one key fewer because it leaves out Fn.
Key counts of standard keyboard layouts
| Layout | ANSI keys | ISO keys | Keys it leaves out |
|---|
| Full size | 104 | 105 | None |
| Tenkeyless (TKL) | 87 | 88 | The number pad |
| 60% | 61 | 62 | Everything outside the main typing area. The F keys, arrows and navigation keys move to an Fn layer. |
What are key rollover and ghosting?
Key rollover is the number of keys a keyboard can register at the same time.
Ghosting is a fault where pressing several keys together registers a key you never pressed. Keyboards that guard against it block one of the keys instead, so that key doesn't turn blue. To check yours, press and hold keys one after another and watch the Held now and Most at once counters.
A keyboard that uses the USB boot report format can send at most six keys plus the modifier keys at once, which is where the six-key rollover (6KRO) label comes from. Keyboards sold with n-key rollover (NKRO) register every key you hold, though some only do it over a cable.
What is keyboard chatter?
Chatter is when one press of a key registers as two or more presses.
It's also called double typing. Our tester flags a key that's pressed again within 50 ms of its release, and the Chatter limit menu changes that number. Raise the limit if doubled letters slip through, or lower it if quick, deliberate double taps get flagged.
If the same key chatters again after you press Reset and test it a second time, the keyboard is the likely cause, not the way you pressed the key.
What can't an online keyboard test detect?
A web page only sees the key presses that the operating system and the browser pass on.
- The Fn key. The W3C code list describes Fn as a hardware key that typically sends no code of its own, so the tester usually can't see it.
- System shortcuts. On Windows, Alt+Tab and Ctrl+Alt+Delete go to the system first, so the page never sees the Tab or Delete. Test those keys on their own.
- Browser shortcuts. Ctrl+W, Ctrl+T and Ctrl+N (Cmd on a Mac) belong to the browser and may close or open tabs and windows before the page can react, so leave them out of rollover tests.
- Polling rate and input lag. Key events reach the page only after the operating system and the browser have handled them, so a page can't measure the keyboard's own timing.
What should you do when a key fails the test?
First, retest the key with the keyboard on another USB port or computer, if you can.
- Clean around the key. Unplug or switch off the keyboard, then clear dust and crumbs from around it.
- Check the accessibility settings. Filter Keys on Windows and Slow Keys on a Mac change how the computer accepts key presses, so turn them off while you test.
- Check the wireless connection. Charge or replace the batteries, then pair the keyboard again.
Common mistakes
These keyboard test mistakes make a working key look broken.
- Testing an ANSI keyboard on the ISO layout. An ANSI keyboard has no key between Left Shift and Z, so that spot can never turn green. Choose ANSI if your Enter key is one row tall.
- Testing the F keys in media mode. When the top row changes volume or brightness, it usually doesn't send F1 to F12, so those keys stay plain on the map. Hold Fn to test them. On a Mac, turn off the Show Desktop shortcut before testing F11.
- Pressing keys before the test starts. Until you click the map or type a letter or number, keys like Esc, F1 or the arrows do their usual jobs instead, such as scrolling the page.
Common Use Cases
A keyboard test helps whenever you need proof that every key works.
- Checking a new or used keyboard. Test every key before the return window closes.
- Finding dead keys after a spill. The keys that never turn green after a full pass are the ones to clean or replace.
- Confirming a switch swap. After you replace switches on a mechanical keyboard, press each changed key to check that it registers.
- Testing rollover for games. Hold your usual key combinations and see whether every key turns blue.
Building keyboard shortcuts for a web app? The Keyboard Event Code Tester shows the event.key, event.code and keyCode values of each key.
Frequently Asked Questions
How do you know if a keyboard key is not working?
A key isn't working if pressing it sends nothing, so it never turns green in the tester. If it also fails on another computer, the cause is the keyboard itself, either a fault or a built-in setting such as a gaming keyboard's Windows key lock.
Can you test a keyboard without installing anything?
Yes, the test runs in the web page, so there's nothing to download or install. You can use it on Windows 10 or 11, macOS, ChromeOS or Linux.
Does the test work on a laptop keyboard?
Yes, choose Tenkeyless for a laptop without a number pad, and ignore keys your laptop doesn't have. If the top row changes volume or brightness, hold Fn to test F1 to F12.
Why doesn't the Fn key light up?
The Fn key is usually handled inside the keyboard, so it sends no code a web page can see. If a top-row key does something different while you hold Fn, Fn works.
Can you test an AZERTY or QWERTZ keyboard?
Yes, keys are matched by position, so the correct key lights up whatever layout your system uses. In Chrome and Edge the labels also follow your layout, and in other browsers most labels update after you press each key.
Does the keyboard tester record what you type?
No, our tester keeps key presses in the open page and never sends them anywhere. Reloading the page clears them, and the tester saves only your ANSI or ISO choice, key labels and chatter limit on your device.
Does the test work with a Mac keyboard?
Yes, on a Mac the key labels switch to Cmd, Option, Control, Return and Delete. Hold Caps Lock until its light comes on, because the key has a short delay to stop accidental presses.
